Free Projection Mapping with OpenFrameworks

Projection mapping, whether performed as intricate alignment to surfaces or simply as a way to get out of basic rectangular viewing ratios, has potential to create a range of visual effects. Now, those capabilities are available to users of the fully free and open source, omni-platform goodness that is OpenFrameworks.

hvfrancesco has built a really brilliant, simple-but-effective, um, open framework for OpenFrameworks. It just does some simple quadrilateral warping math, and amazingly, it’s his first OF code. (In fact, even if you just want to learn that math, it’s worth a look.)

very interesting
i have an question about the quads, i saw when two quads share the same area(quad n 1 and quad n 4), one is chosen (in this case quad n 4), the quad has a property like "bring to front", or whith a internal layer, how you resolve this issue?
Grettings
Adriana